I fill it up before it hits empty. I try not to let my fuel pump work harder than it has to.

 

Where did you get that information?

 

Jeff maybe you should use an aftermarket fuel gauge like autometer.

 

My gauge occasionally says it has about a 1/4 less than whats in there. I usually average 270-280 miles city driving so I fill up whenever I get close. It just does this whenever it wants then goes back to normal and reading accurately.

 

you are correct
i thought i read it on my owners manual, but i was wrong. Since i saw the driffrent numbers, i thought 19.8 was for the GS4 and the 16.5 was for the GS3 just glad you guys caught it.

i was just testing you guys and you guys passed

 

i've used seafoam about a month ago, it did help my mpg slightly.

 

My car does the same exact same thing; The low fuel warning light comes on and I can rarely squeeze more than 16 gallons in the tank. I always thought it was because the fuel level warning was set up extremely conservative. The one exception was one time on a long trip out in the middle of nowhere (Eastern Oregon State) I miss-calculated and put around 60 miles on the car after the low fuel warning light came on. Still only took 18 gallons.